Acids, Bases, & Salts Regents Review

1. According to the Arrhenius theory, an acid is a substance that: A)    Changes litmus from red to blue B)    Changes phenolphthalein from colorless to pink C)    Produces hydronium ions as the only positive ions in an aqueous solution D)    Produces hydroxide ions as the only negative ions in an aqueous solution Correct Answer: Option C - Produces hydronium ions as the only positive ions in an aqueous solution

1. An acidic solution could have a pH of: B)    7 C)    10 D)    14 Correct Answer: Option A - 3.5

11. Some alternate acid base theories define an acid as any species that can: A)    Donate an electron B)    Donate a proton C)    Accept a proton D)    Accept an electron Correct Answer: Option B - Donate a proton In the Brønsted-Lowry theory is an acid-base theory in which, an acid is defined as any chemical species that is able to lose, or "donate" a hydrogen ion (proton), and a base is a species with the ability to gain or "accept" a hydrogen ion (proton).

12. When HCl(aq) is exactly neutralized by KOH(aq), the hydrogen ion concentration in the resulting mixture is: A)    Always equal to the concentration of the hydroxide ions B)    Sometimes greater and sometimes less than the concentration of the hydroxide ions C)    Always less than the concentration of the hydroxide ions D)    Always greater than the concentration of the hydroxide ions Correct Answer: Option A - Always equal to the concentration of the hydroxide ions Neutralization is a chemical reaction whereby an acid and a base react to form water and a salt.

16. A student wishes to prepare approximately 100 milliliters of an aqueous solution of 6M HCl using 12 M HCl. Which procedure is correct? A)    Adding 50 mL of water to 50 mL of 12 M HCl while stirring the mixture steadily. B)    Adding 50 mL of 12 M HCl to 50 mL of water and then stirring the mixture steadily. C)    Adding 50 mL of 12 M HCl to 50 mL of water while stirring the mixture steadily. D)    Adding 50 mL of water to 50 mL of 12 M HCl and then stirring the mixture steadily. Correct Answer: Option C - Adding 50 mL of 12 M HCl to 50 mL of water while stirring the mixture steadily. Adding acid to water prevents the acid from splattering. Never add water to acid.

17. In which laboratory process could a student use 0 17. In which laboratory process could a student use 0.10 M NaOH(aq) to determine the concentration of an aqueous solution of HBr? A)    Decomposition of the solute B)    Chromatography C)    Evaporation of the solvent D)    Titration Correct Answer: Option D - Titration

NH3(g) + H2O(l) → NH4+(aq) + OH-(aq) 18. Given the balanced equation representing a reaction: NH3(g) + H2O(l) → NH4+(aq) + OH-(aq) According to one acid-base theory, the NH3(g) molecules act as A)    An acid because they accept H+ ions B)    An acid because they donate H+ ions C)    A base because they accept H+ ions D)    A base because they donate H+ ions Correct Answer: Option C - A base because they accept H+ ions According to the acid base theory H+ ions or hydronium ions are given out by acids and accepted by bases. Since, NH3(g) accepts H+ ion to become NH4+ in the above equation NH3 molecule acts as a base.

19. What volume of 0.120M HNO3(aq) is needed to completely neutralize 150 milliliters of 0.100 M NaOH(aq)? A)    125 mL B)    62 mL C)    180 mL D)    360 mL Correct Answer: Option A - 125 mL In titration method, (Volume of acid) x (molarity of the acid) neutralizes an equal volume of base x the molarity of the base VAcid x MAcid = VBase x MBase where V = volume and M = molarity of HNO3 and NaOH. i.e. 0.120M x V = 0.100M x 150ml Volume of HNO3 = (0.100 x 150) / 0.120 = 125mL of 0.120M HNO3

20. The following data were collected at the endpoint of a titration performed to find the molarity of an HCl solution. Volume of acid (HCl) used = 14.4 mL Volume of base (NaOH) used = 22.4 mL Molarity of standard base (NaOH) = 0.20 M What is the molarity of the acid solution? A)    1.5M B)    0.13M C)    0.31M D)    0.64 M Correct Answer: Option C - 0.31M

21. The reaction between hydroxyl ions and hydrogen ions is called: A)    Analysis B)    Neutralization C)    Hydrolysis D)    Decomposition Correct Answer: Option B - Neutralization Neutralization is a chemical reaction whereby an acid and a base react to form water and a salt.

22. A water solution of H2S is: A)    Neutral B)    Basic C)    Acidic D)    Salty Correct Answer: Option C - Acidic

24. The acid present in vinegar is: A)    Hydrogen sulfide B)    Acetic acid C)    Nitric acid D)    Sulfuric acid Correct Answer: Option B - Acetic acid

Correct answer: (2)

Correct answer: (4) BaSO4

Correct answer: (3) HBr

Correct answer: (3) H2SO4(aq) and Ca(OH)2(aq)

3) is the correct answer; 

3) H3PO4 is the correct answer

4) KOH is the correct answer

(2) bromthymol blue is the correct answer.

Which formula represents a salt? KOH KCl CH3OH CH3COOH Correct answer is KCl

Which solution will turn litmus from red to blue? H2S(aq) NH3(aq) SO2(aq) CO2(aq) Correct answer is NH3

Which solution will change litmus from blue to red? NaOH(aq) NH4OH(aq) CH3OH(aq) CH3COOH(aq) Correct Answer is CH3COOH(aq)

Which ion is produced when an Arrhenius base is dissolved in water? H+, as the only positive ion in solution H3O+, as the only positive ion in solution OH-, as the only negative ion in solution H-, as the only negative ion in solution Correct Answer OH-, as the only negative ion in solution